关键词: 双悬臂梁试样, 权函数, 位移加载条件, 应力强度因子, 裂纹嘴位移

Abstract:

Double cantilever beam(DCB) specimen has important applications in materials' damage tolerance properties evaluation, especially for experimental determination of the stress corrosion cracking threshold(K_ISCC). Because of the particular specimen geometry, crack surface displacement loading at a specific position which is a certain distance away from the specimen edge(crack mouth) is commonly used. However, displacement measurement at the loading position is not only time-consuming but also inaccurate. For the DCB specimen, the most convenient and accurate displacement measurement location is at the crack mouth. In this paper, through finite element calculations for a reference load case and by using the classical weight function method for the edge crack geometry, analytical weight function for the DCB specimen is developed. Comparisons and verification have been conducted using the complex variable function Taylor series expansion weight function. Furthermore, from the specific loading point displacement, stress intensity factor for uniform stress loading at the corresponding crack surface location is obtained by inverse calculation. An analytical expression between the stress intensity factor and the crack mouth displacement is derived for DCB specimen subjected to the crack surface displacement loading at specific position. Thus, a solid foundation is laid for the evaluation of materials' damage tolerance properties using the DCB specimen, especially for K_ISCC measurement automation with high accuracy.

Key words: double cantilever beam specimen, weight function, displacement loading condition, stress intensity factor, crack mouth displacement